Boilers for heating various liquids may be employed in a variety of domestic, commercial and/or industrial applications. For example, a common application is a boiler for heating water to make hot beverages like coffee, tea, etc. An example boiler may comprise a heating element (e.g., a heating tube) immersed in a vessel containing the water to be heated. Heating elements may run on electricity, gas, etc. A problem that may affect the performance of boilers that heat water is scaling. Scaling in boiler may be caused by impurities in the water being deposited on the boiler heating tubes. These depositions, which are predominantly made up of silica, calcium or magnesium salts, have very low thermal conductivity compared to materials commonly used to make boiler tubes (e.g., copper or steel). Scaling in a boiler may substantially reduce the heat transfer rate from heating tube to the water, which may at least reduce the operational efficiency of the boiler, but at its most serious may also create a potentially hazardous operating condition.
In particular, scaling may cause potentially hazardous hot spots on boiler heating tubes. If unchecked, scaling may act as an insulator that progressively reduces boiler efficiency due to heat retardation. Scale built-up may eventually cause a boiler heating tube to overheat, rupture, etc. Returning to the hot beverage example, it is especially important to ensure that boilers in a hot beverage vending machine remain scale free, as scale not only may affect the safe operation and efficiency of the vending machine as discussed above, but may also affect the water quality, and subsequently, the taste of dispensed beverages. Presently, boilers in hot beverage vending machines are replaced on routine basis as per traditional preventive maintenance principles (e.g., based on a manufacturer's recommendation). As a result, the replacement of boilers may occur frequently in situations where replacement is unnecessary based on the actual condition of the boiler. Replacing boilers that do not actually require replacement may result in, for example, a waste of money and inconvenience for the vending machine operators and their customers.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications and variations thereof will be apparent to those skilled in the art.